Joel K. W. Yang, Kevin T. P. Lim, Hailong Liu, Yejing Liu
Researchers from the Singapore University of Technology and Design (SUTD) have invented a new type of anti-counterfeiting device that can be useful for counterfeit deterrence of important documents such as identity cards, passports and banknotes. Calling it “holographic colour prints”, the research team led by Associate Professor Joel Yang demonstrated an optical device that appears as a regular colour print under white light, but projects up to three different images onto a distant screen when lit up with laser pointers. Unlike regular diffractive optical elements that have a frosted-glass appearance and projects only single images, these new holographic colour prints can be a stronger deterrent to counterfeiters while looking pretty at the same time. In addition, the prints consist of nano-3D-printed polymer structures and find particular use in optical document security.
You can find more details at https://www.sutd.edu.sg/Research/Research-News/2019/1/Holographic-color-printing-for-optical-security